Conventional slow cooker comprises a liner container and a lid disposed on the top rim of the container. The lid is typically not securely engaged with the container. The user is likely to move the cooker or the liner container containing food after the food is well cooked. The lid tends to slide off during movement because there is no secure connection between the liner container and the lid. Furthermore, the shaking caused by the movement can possibly cause spillage of the liquid content in the container, and thus may burn the user.
Chinese patent no. CN 200920198406.X discloses a slow cooker having a touch control panel, which comprises a working pot covered by a lid. A handle comprised of an upper part and a lower part is symmetrically fixed near the top edge of working pot. A spring hole is arranged in the middle of the lower part for accommodating a spring and a steel bead. A latch is slidably arranged between the upper and lower parts, and the movement of the latch is limited by the steel bead. A closed sealing ring, made of silicon gel, is arranged below the periphery of the lid to achieve seal connection between the lid and the working pot. The latch provided between the working pot and the lid is used to seal the working pot. However, this design has too many parts, resulting in high cost and difficulty of assembly. Moreover, the latch is subject to large area of friction, causing non-smooth operation. Further, the steel bead is positioned by the elastic force of the spring which may deteriorate during long term use, resulting in high possibility of latch release.
Chinese patent no. CN 200710005602 discloses a slow cooker comprising a housing, a container and a lid. The lid includes a gasket around an outer edge thereof and is shaped and sized to cover the opening of the container. At least one over-the-center clip is mounted to the side all of the housing, the clip being selectively engageable with the lid to retain the lid in sealing engagement with the container, in order to inhibit leakage of the food stuffs from the interior of the container. The clip includes a hook and a lever, the hook being selectively engageable with the lid to selectively retain the lid in sealing engagement with the container. A catch has to be provided to the lid in order to engage the hook of the clip. This will lead to additional cost and more complicated manufacturing process for mounting such a catch, particularly on a glass lid as predominately used in slow cookers.
Additionally, the locking structure in the above disclosed slow cookers are fixed on the housing or container and can not be disassembled or be used for other slow cookers. The locking structure can not be easily repaired or replaced, resulting in a poor versatility.